A probe in an electronic scanning ultrasonic diagnostic apparatus that transmits and receives ultrasonic waves has heretofore been constituted by arranging, on a backing material, a plurality of transducers each of which comprising a piezoelectric transducer, an acoustic lens, and an acoustic matching layer provided between the piezoelectric transducer and the acoustic lens.
In this probe, a transducer of a narrow width having the acoustic matching layer vibrates accompanied, however, by a deformation in the direction of thickness, by a deformation in the direction of width and, hence, by a reduction in the conversion efficiency in the direction of thickness. Further, since the vibration in the direction of width interferes with the vibration in the direction of thickness, the surface of the transducer goes out of vibration of a uniform amplitude deteriorating the image of the ultrasonic diagnostic equipment.
A probe obtained by arranging the vibrators that have a fibrous material dispersed in the acoustic matching layer has been disclosed in JP-A-10-75953. However, this fibrous material is used for realizing a low heat conduction, and the direction of fiber has not been set by taking the Young's modulus of the fiber and the Poisson's ratio into consideration. Therefore, the above problem cannot be solved by the above prior art.